global.uuid = function(split = true) {
  var d = new Date().getTime()
  if (window.performance && typeof window.performance.now === 'function') {
    d += performance.now()
  }
  let uuidTpl = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'
  if (!split) {
    uuidTpl = 'xxxxxxxxxxxx4xxxyxxxxxxxxxxxxxxx'
  }
  const uuid = uuidTpl.replace(/[xy]/g, function(c) {
    const r = (d + Math.random() * 16) % 16 | 0
    d = Math.floor(d / 16)
    return (c === 'x' ? r : (r & 0x3) | 0x8).toString(16)
  })
  return uuid
}
